TITLE: Shilla and MAGEC Systems for Growing Children with Scoliosis: A Review of the Clinical Benefits and Cost-Effectiveness

Transcription

1 TITLE: Shilla and MAGEC Systems for Growing Children with Scoliosis: A Review of the Clinical Benefits and Cost-Effectiveness DATE: 17 January 2013 CONTEXT AND POLICY ISSUES Early-onset scoliosis (EOS) is a structural, lateral curvature of the spine in children younger than five years of age. In Europe, it affects 1-2 children out of every 10,000 people a rate that is four times higher than in the USA. 1 With EOS there is progressive deformity of the spine and abnormal pulmonary function. 1 Management of EOS depends on the age of the patient, type and severity of the curve, and progression of the condition. Management of EOS included nonsurgical treatment such as casting or bracing of the spine, and surgical procedures such as spinal fusion and spinal implants. 1,2 Currently used spinal implants comprised of single rod, dual rod, and vertical expandable prosthetic titanium ribs (VEPTR). 2 The use of current growing rods, requiring general anesthesia and invasiveness of repeated lenghthening surgeries, has resulted in suboptimal results, including implant pullout, rod breakage, infections and alignment problems that require multiple revision surgeries. 3 Recently, novel techniques such the Shilla procedure (Medtronic Spine Inc., Memphis, TN) and magnetic growing rods [Magnetic Expansion Control System (MAGEC Ellipse Technologies, Inc., Irvine, CA) and the Phenix rod (Phenix Rod, France)] have been developed in the hope to overcome the drawbacks of current techniques. 4 The Shilla system in which the rods are fixed to the screws at the apex but can slide at the proximal and distal ends, allows for curve control while permitting spine growth without the need for surgical lenghthening. 4,5 The MAGEC system, which could be comprised of a single rod or dual rod system that could be elongated with an external magnet, was also designed to avoid lenghthening surgeries. 4,5 Clinical effectiveness of the techniques on patients with scoliosis are usually based on radiographic evaluation criteria such as Cobb angle changes and spinal height gain. This report will provide a review of the clinical and cost effectiveness of the Shilla and the MAGEC systems for growing children with scoliosis. Disclaimer: The Rapid Response Service is an information service for those involved in planning and providing health care in Canada. Rapid responses are based on a limited literature search and are not comprehensive, systematic reviews. The intent is to provide a list of sources and a summary of the best evidence on the topic that CADTH could identify using all reasonable efforts within the time allowed. Rapid responses should be considered along with other types of information and health care considerations. The information included in this response is not intended to replace professional medical advice, nor should it be construed as a recommendation for or against the use of a particular health technology. Readers are also cautioned that a lack of good quality evidence does not necessarily mean a lack of effectiveness particularly in the case of new and emerging health technologies, for which little information can be found, but which may in future prove to be effective. While CADTH has taken care in the preparation of the report to ensure that its contents are accurate, complete and up to date, CADTH does not make any guarantee to that effect. CADTH is not liable for any loss or damages resulting from use of the information in the report. Copyright: This report contains CADTH copyright material. It may be copied and used for non-commercial purposes, provided that attribution is given to CADTH. Links: This report may contain links to other information available on the websites of third parties on the Internet. CADTH does not have control over the content of such sites. Use of third party sites is governed by the owners own terms and conditions.

2 RESEARCH QUESTIONS 1. What are the clinical benefits and harms associated with Shilla and MAGEC in growing children with scoliosis? 2. What is the cost-effectiveness of Shilla or MAGEC compared with dual growing rods in growing children with scoliosis? KEY FINDINGS There were no studies comparing the Shilla system or the MAGEC rods to current dual growing rods. Data from two studies with methodological limitations showed that the MAGEC rods can provide adequate curve correction and spine distraction, with no major complications. MAGEC dual rods seem to have better clinical benefits than MAGEC single rod systems. The instrumental cost of the MAGEC system is higher than the current growing rods. METHODS Literature Search Strategy A limited literature search was conducted on key resources including PubMed, The Cochrane Library (2012, Issue 12), University of York Centre for Reviews and Dissemination (CRD) databases, Canadian and major international health technology agencies, as well as a focused Internet search. Methodological filters were applied to limit retrieval to health technology assessments, systematic reviews, meta-analyses, randomized controlled trials, non-randomized studies, and economic studies. The search was also limited to English language documents published between January 1, 2003 and December 10, Selection Criteria and Methods One reviewer screened the titles and abstracts of the retrieved publications and examined the full-text publications for the final article selection. Selection criteria are outlined in Table 1. Table 1: Selection Criteria Population Pediatric population (<10 years) with scoliosis Intervention Shilla procedure MAGEC rods Comparator Dual growing rods Outcomes Clinical benefit/harms Cost-effectiveness (economic risks associated with devices and cost of treatment) Study design Health technology assessments, systematic reviews, meta-analyses, guidelines. If no systematic reviews were identified, randomized controlled trials (RCTs), non-rcts and case studies were selected for inclusion. Shilla and MAGEC Systems for Growing Children with Scoliosis 2

3 Exclusion Criteria Articles were excluded if they did not meet the selection criteria in Table 1, if they were published prior to January 2003, if they were duplicate publications of the same study, or if they were referenced in a selected systematic review. Critical Appraisal of Individual Studies The quality of the included prospective observational study was assessed using Downs and Black checklist. 6 Numerical scores were not calculated. Instead, the strengths and limitations of individual studies are summarized and presented. A formal quality assessment of case reports was not conducted since these study designs are considered to be inferior quality SUMMARY OF EVIDENCE Quantity of Available Evidence The literature search yielded 514 citations. Four additional studies were identified by searching the grey literature. After screening of abstracts, 11 potentially relevant studies were selected for full-text review. Two studies were included in the review. The PRISMA flowchart in Appendix 1 details the process of the study selection. Summary of Study Characteristics A detailed summary of the included studies is provided in Appendix 2. Study design The report included one prospective non-randomized study 7 and one case series. 8 Both studies were published in Length of follow-up was 10 months in the prospective non-randomized study and 24 months in the case series. Population The prospective study 7 included 14 patients (mean age 8 years plus 10 months) with EOS (five patients with single rod and 9 with dual rods). The case series 8 included two patients with EOS (age 5 years plus 8 months, and 12 years plus 1 month). In the case series, patient 1 had single MAGEC rod, and patient 2 had dual MAGEC rods. Interventions and comparators In both studies, all patients received either MAGEC system single or dual rods. 7,8 Neither of the included studies included other rod types as comparators. Outcomes The main outcome measures of the included studies were spinal curvature correction and spinal height gain. 7,8 The case series reported on instrument costs. Shilla and MAGEC Systems for Growing Children with Scoliosis 3

4 Summary of Critical Appraisal The included trials comprised one prospective non-randomized study, 7 and one case-series. 8 The prospective study included a small sample size (n = 14), was confounded by selection bias, and did not have a comparator group. The case series had two patients, did not have a comparator group and by design is considered to be of low scientific rigour. Details of the strengths and limitations of the prospective study are summarized in Appendix 3. A formal assessment of the case series was not performed. Summary of Findings Main findings of included studies are summarized in detail in Appendix What are the clinical benefits and harms associated with Shilla and MAGEC in growing children with scoliosis? There was no study found that compared the clinical effectiveness and harms of the Shilla system or MAGEC rods to current dual growing rods. The literature search found two noncomparative studies, one observational study 7 and one case series, 8 that reported the clinical effectiveness of the MAGEC rods on children with early-onset scoliosis. This limited evidence showed that the MAGEC rods provide adequate curve correction and spine distraction, with no major complications. The observational study was a multi-center non-randomized study that included 14 patients (mean age of 8 years plus 10 months) with early-onset scoliosis, using single or dual MAGEC rods, for a mean follow-up of 10 months. 7 Clinical effectiveness of the MAGEC rods was evaluated by measurement of the Cobb angle change and spinal length gain. Data showed that the magnetic controlled growing rod provided curve correction, and spinal distraction, and the changes were smilar to expected changes with standard growing rods. There was no major intra-operative and post-operative complications. Compared to MAGEC single rod system, MAGEC dual rod system provided better monthly growth of the T1 S1 segment, and the difference was statistically significant. The case series included 2 patients (aged 5 years and 8 months and 12 years and 1 month) with early onset scoliosis, using the MAGEC rods, for a follow-up time of 24 months. 8 Clinical effectiveness of the MAGEC rods was evaluated by measurement of the Cobb angle change and spinal length gain. Data showed that the magnetic controlled growing rod provided satisfying curve correction and spinal distraction in both patients. Patient 2 who had dual MAGEC rods had better instrumental segment length gain than patient 1 who had single MAGEC rods system (ststistical significance not reported) There was no study found on the clinical effectiveness and harms of the Shilla system. 2. What is the cost-effectiveness of Shilla or MAGEC compared with dual growing rods in growing children with scoliosis? There was no study found that compared the cost-effectiveness of Shilla or MAGEC with dual growing rods in growing children with scoliosis. The case series study reported MAGEC Shilla and MAGEC Systems for Growing Children with Scoliosis 4

5 instrumentation costs of HK$50,000 or US$6,451 and traditional growing rod costs of HK$25,000 or US$3, Limitations The available evidence on the clinical effectiveness of the Shiila and MAGEC systems is very limited in quantity and very weak in rigour. Non-randomized studies may be prone to selection bias, and the included study may have lacked adequate statistical power. Case studies are considered to be of inferior quality as they lack comparator or control groups and report on isolated events. There were no clinical or economic studies identified comparing the Shilla and MAGEC systems to current dual growing rod system. CONCLUSIONS AND IMPLICATIONS FOR DECISION OR POLICY MAKING One prospective observational study and one case series (two cases) found that the MAGEC rods can provide adequate curve correction and spine distraction, with no major complications. However, these findings should be interpreted with caution due to methodological concerns. The changes are comparable with expected changes using standard growing rods. Dual MAGEC rods may give better clinical benefits than single MAGEC rod. The MAGEC instrumentation costs were higher than current dual growing rods, but the difference may be offset by less frequent operations by the former. Randomized controlled trials with larger population size, and cost-effectiveness studies are needed to confirm the findings. PREPARED BY: Canadian Agency for Drugs and Technologies in Health Tel: Shilla and MAGEC Systems for Growing Children with Scoliosis 5

6 REFERENCES 1. Debnath UK. Current concepts in the management of early-onset idiopathic scoliosis. Pediatr Health. 2010;4(3): Lenke LG, Dobbs MB. Management of juvenile idiopathic scoliosis. J Bone Joint Surg Am Feb;89 Suppl 1: Wick JM, Konze J. A magnetic approach to treating progressive early-onset scoliosis. AORN J Aug;96(2): Tis JE, Karlin LI, Akbarnia BA, Blakemore LC, Thompson GH, McCarthy RE, et al. Early onset scoliosis: modern treatment and results. J Pediatr Orthop Oct;32(7): Gomez JA, Lee JK, Kim PD, Roye DP, Vitale MG. "Growth friendly" spine surgery: management options for the young child with scoliosis. J Am Acad Orthop Surg Dec;19(12): Downs SH, Black N. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. J Epidemiol Community Health [Internet] Jun [cited 2013 Jan 10];52(6): Available from: 7. Akbarnia BA, Cheung K, Noordeen H, Elsebaie H, Yazici M, Dannawi Z, et al. Next generation of growth-sparing technique: preliminary clinical results of a magnetically controlled growing rod (MCGR) in 14 patients with early onset scoliosis. Spine (Phila Pa 1976 ) Oct Cheung KM, Cheung JP, Samartzis D, Mak KC, Wong YW, Cheung WY, et al. Magnetically controlled growing rods for severe spinal curvature in young children: a prospective case series. Lancet May 26;379(9830): Shilla and MAGEC Systems for Growing Children with Scoliosis 6

7 Appendix 1: Selection of Publications 514 citations identified from electronic literature search and screened (abstracts) Four potentially relevant reports retrieved from other sources (grey literature, hand search) 507 citations excluded 11 potentially relevant articles retrieved for scrutiny (full text) 9 reports excluded 2 reports included in review Shilla and MAGEC Systems for Growing Children with Scoliosis 7

8 Appendix 2: Characteristics of Included Studies Table A1: Characteristics of Included Clinical Trials First Author, Year, Country, Study design; length of follow-up Intervention Comparator(s) Patient characteristics Main clinical outcomes reported Akbarnia, USA Cheung, HongKong Multi-center prospective nonrandomized study. 10-month follow-up (total 68 distractions for 14 patients) Single-center case series (2 cases) 24-month follow-up (total 43 distractions for 2 patients) MAGEC system No comparator MAGEC system No comparator 14 patients with EOS (5 patients with single rod system and 9 patients with dual rod system); mean age 8y + 10m 2 patients with EOS (1 patient with single rod system and 1 patient with dual rod system); age 5 y + 8m and 12y + 1 m m: month; MAGEC: Magnetic Expansion Control System ; EOS: early-onser scoliosis; y: years Cobb angle change Spinal height increase Complications Cobb angle change Spinal height increase Complications Shilla and MAGEC Systems for Growing Children with Scoliosis 8

9 Appendix 3: Summary of Critical Appraisal of Included Studies Table A2: Summary of Critical Appraisal of Included Studies First Author, Strengths Publication Year Akbarnia, hypothesis clearly described method of selection from source population and representation described main outcomes, interventions, patient characteristics, and main findings clearly described estimates of random variability and actual probability values provided losses to follow-up described Limitations patients not randomized unclear whether power calculation was performed to determine adequate sample size Shilla and MAGEC Systems for Growing Children with Scoliosis 9

10 Appendix 4: Main Study Findings and Authors Conclusions Table A3: Main Study Findings and Authors Conclusions First Author, Main Study Findings Publication Year Research question 1 (long-term clinical effectiveness of Shilla and MAGEC) Akbarnia, Cobb angle correction (mean) Cobb angle changed from 60 to 34 after surgery and 31 at latest follow-up (mean 10 months) Single rod system: 46% change Dual rod system: 48 % change Differences in the initial correction and final correction between the 2 techniques (single rod and dual rod) was not statistically significant ( P = 0.91 and P = 0.85) T1 T12 height gain (mean) Single rod: 7.6 mm (1.09 mm/month) Dual rod: mm (1.97 mm/month) Differences were not statistically significant between the 2 systems (P = 0.21) T1 S1 height gain (mean) Single rod: 9.1 mm (1.27 mm/month) Dual rod: 20.3 mm (3.09 mm/month) Differences were statistically significant between the 2 systems (P < 0.05) Authors Conclusions Preliminary results indicated MCGR was safe and provided adequate distraction similar to standard GR. DR achieved better initial curve correction and greater spinal height during distraction compared to SR. No major complications were observed during the FU (p 3) Cheung, Complications (number of patients with events) Superficial wound infection: in 1 single rod patient (1/5) Prominent implant: in 1 dual rod patient (1/9) Partial loss of initial height: in 3 single rod patients (3/5) There was no neurologic deficit or implant failure Cobb angle correction (mean) Cobb angle changed from 67% (SD 10 ) to 29% (SD 4 ) at 24 months Instrumental segment length gain (mean): Single rod (patient1): 1.4 mm per distraction (SD 0.7 mm) Dual rod (patient 2): 1.9 mm per distraction (SD 0.6 mm) for right rod and 1.7 mm per distraction (SD 0.8 mm) for left rod Overall: 1.9 mm per distraction (SD 0.4 mm) Complications (number of patients with events) No pain as measured by VAS Superficial wound infection: in 1 patient (1/2) No prominent implant, There was no neurologic deficit or implant failure Both patients satisfied with medical management; good function and acitivity, self image, and mental health scores as measured by SRS-30 The MCGR procedure can be safely and eff ectively used in outpatient settings, and minimises surgical scarring and psychological distress, improves quality of life, and is more cost-eff ective than is the traditional growing rod procedure ( p 1967) Shilla and MAGEC Systems for Growing Children with Scoliosis 10

11 Table A3: Main Study Findings and Authors Conclusions First Author, Main Study Findings Publication Year Research question 2 (cost-effectiveness of Shilla and MAGEC) Cheung, MAGEC instrumentation costs: HK$50,000; US$6,451 Traditional growing rod: HK$25,000; US$3,225 Authors Conclusions The MCGR procedure can be safely and eff ectively used in outpatient settings, and minimises surgical scarring and psychological distress, improves quality of life, and is more cost-eff ective than is the traditional growing rod procedure ( p 1967) SD: standard deviation; SRS-30 : Scoliosis Research Society questionnaire, version 30; VAS: visual analogue scale Shilla and MAGEC Systems for Growing Children with Scoliosis 11